Switched lattice reduction-aided detection techniques for MIMO systems

Lattice reduction (LR) aided multiple-input- multiple-output (MIMO) linear detection can achieve the diversity order as the maximum likelihood detection (MID). By employing the most commonly used Lenstra, Lenstra, and L. Lov'asz (LLL) algorithm, an equivalent channel matrix which is shorter and nearly orthogonal is obtained. The noise enhancement can be greatly reduced by employing the LR-aided detection. However, the LLL algorithm cannot guarantee to find the optimal basis. The optimal lattice basis can be found by the Korkin and Zolotarev (KZ) reduction which is infeasible in practice due to its high complexity. In this paper, a switched algorithm is proposed based on the complex LLL (CLLL) algorithm to approach the optimal performance while maintaining a reasonable complexity. The linear and successive interference cancelation (SIC) detection algorithms are devised based on a strategy that permutes the lattice bases and switches to the best available set. The results of simulation show that the proposed techniques outperform existing methods.